Behavior of havoc operator in combination with definite assignment is not well explained in error messages

[keyboardDrummer]

I believe in the following example, Dafny handles havoc assignment * differently for types that have a default value and those that do not, but this is not reflected in the error messages.

method myMethod(m: int) returns (b:bool) { return true; }

method mainHavoc(){
    var t: int := *;
    var r:= myMethod(t);    // no error
}

trait T extends object {}
method myMethod2(m: T?) returns (b:bool) { return true; }

method mainHavoc2(){
    var t: T := *; // error on the next line goes away if change this to T?
    var r:= myMethod2(t);    //FAILS: variable 't', which is subject to definite-assignment rules, might be uninitialized here
}